Air conditioner having electrostatic air filter therein



March 26, 1957 R. F. CONNOR 2,786,544

AIR CONDITIONER HAVING ELECTROSTATIC AIR FILTER THEREIN Filed Dec. 22, 1954 2 Shets-Sheet 2 n n lnnnnnnnnnnnnn :1.

U UUUuUuuuuuuuu llllllllflllllllllllllIII INVENTOR. RALPH F. CONNOR A 7' TORNEY United States Patent AIR CONDITIONER HAVING ELECTROSTATIC AIR FILTER THEREIN Ralph F. Connor, Evansville, Ind., assignor, by mesne assignments, to WhirlpoolrSeege'r Corporation, a corporation of Delaware Application December 22, 1954, Serial No. 477,028

7 Claims. (Cl. 1831-7) This invention relates to air conditioning apparatus but is more specifically concerned with improvedair filtering means suitable for incorporation in air conditioning units.

Heretofore various types of electrostatic precipitators have been employed for filtering and cleaning purposes by precipitating dust particles and the like out of the air and hence structures of this type are generally Well known in the industry. Although such precipitator units have been known to have been utilized singly as Well as in combination with air conditioning apparatus in the larger or commercial type of installations, their use with the small windovwmounted, portable, or self-contained type of air conditioning unit is believed to be virtually unknown. In the conventional electrostatic precipitator unit dust particles or other particulate matters are usually deposited or precipitated onto the surfaces of an electrically charged electrode and then such deposits are subsequently removed therefrom by any one of a variety of different means. The most popular and frequently used method for removing such deposits has been by washing with a suitable liquid which is either applied as an intermittent stream or as a continuous stream that flows in the form of a film of the liquid over the surface of the collecting electrode. Each of these applications, of course, requires the use of complicated and expensive washing devices and controls as well as pipe, tubing, or conduit connections to suitable sources or' supplies of washing liquids and, consequently, have never found much favor with nor been entirely satisfactorily used in the smaller ings'and objections and which is readily suitable for incorporation into a portable-type air conditioning unit.

Another object is to provide an improved air filtering means for an air conditioning unit.

A further object is to provide a simple and inexpensive means for removing collections or deposits of airborne particles such as dust, smoke and the like from the surfaces of one of the electrodes in an electrostatic precipitator device.

A still further object is to provide an electrostatic precipitator device wherein collections or deposits of precipitated matter are washed away by moisture condensed from the air that is being filtered or cleaned by said device.

A yet still further object is to provide an air eonditionin g unit that utilizes moisture condensed out of air being cooled as a washing liquid for removing coll t or d p s t o electro ta sa y presinitsted pa 2,786,544 a t er- ,6... .?5

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matter from the surfaces of the refrigerant evaporator responsible for the production of the condensate.

Another important object is to provide a means for continuously washing deposits off the surface of a precipitating electrode incorporated as a component of an electrostatic precipitator device in an air conditioning unit.

The foregoing and other objects and features of the invention will become apparent as the disclosure is more fully made in the following detailed description of'a' preferred embodiment of the invention as illustrated in the accompanying sheet of drawings, in which:

Fig. 1 is a side elevational view, with a side wall re-, moved, of an air conditioning unit incorporating the present invention therein;

Fig. 2 is a top plan view, with top wall removed, of the air conditioning unit shown in Fig. 1; v

Fig. 3 is a vertical sectional view taken on the line 33 of Fig. 1 and shows particularly the dust particlecharging electrode of the device; and

Fig. 4 is a schematic wiring diagram of the electrical circuit and apparatus used with the electrostatic pre cipitator. 7

Referring now to the drawings, it will be noted that a typical window-mounted type of air conditioner unit has been utilized for purposes of depicting a preferred embodiment of the present invention. Since units of this type are usually small and self-contained and are 1 Ttab1 r f e antarrying sonds tswill pron. es;

readily adaptable for movement from one window to another, they are frequently referred to as portable units, A unit of this type, which is indicated generally by the reference numeral 1!), is usually fashioned with a base; member 11 that is suitably positioned within a removable casing or housing-like cabinet 12 and said base ordinarily provides the structure upon which refrigeration apparatus is fixedly positioned while the unit, in turn, is removably mounted, by well-known means (not shown); in a window frame structure in a wall of the space to be; cooled or air-conditioned. The refrigeration apparatus which is generally conventional includes a refrigerant condenser 13, a condenser fan 14 and its associated shroud 15 and driving motor 16, and a motor-compressor 17,. all of which are mounted on one side of a dividing wall or partition member 18 that divides the cabinet into an outer or high pressure side compartment 19 and an inner: or low pressure side compartment 20. Openings such" as 21 and 22 in the walls of said outer compartment "provide for communication with the outside atmosphere so said apparatus may be dissipated.

In the inner or low-side compartment there is provided a generally conventional air filtering element, such the well-known removable glass fiber that or pad illti's v tra d at 2, h ch is upp rt 'b y a o ablydiise. posed adjacent a cabinet wall opening 24 and coininuni,

cates with the space to be cooled or air eonditi'oned through said opening. Spacedinwardly from said filter is a conventional refrigerant evaporator eooler 25 w hic d n ta ou 26 wi h h h .is rotat bl posed a fan or air Wheel blower 27 that is drivingly 1c nected with the fan driving motor 16 Air 'fromjthe; space to be cooled normally passes into the low-side con} pa'rtment 20 of said cabinet through the opening 2.4 and through the filtering element 23 and into heat exchange relation with the evaporator 25, where the heat thereof e o d n t e is diseharged b th f n 27 thr ugh.

a cabinet wall opening such-asZS, back into the spacey;v

being cooled. ljt will be understgod, of

for connecting the various apparatus together in an operative refrigeration system having suitable refrigerant therein, but the details thereof have not been shown for purposes of clarity and simplicity in the drawings. A shallow condensate collecting pan a disposed beneath the evaporator 25 collects condensate dripping or draining therefrom and a conduit 290 carries said condensate to a shallow collector pan 13!: positioned beneath the condenser 13. Condensate collected or drained in the pan 13a is subsequently evaporated directly by the heat of the condenser 13 or else is picked up by the fan 14 and sprayed onto the surfaces of said condenser in accordance with well-known practices in the industry.

. Now in accordance with the specific teachings of the present invention there is provided in the space between the filter element 23 and evaporator 25 an electrical conductor that serves as a charging electrode 2.9 which is fixedly disposed in the path of the air flowing to and from the spacebeing cooled. This electrode which may take a variety of shapes or forms is illustrated as fashioned to resemble a figure H with all of said conductor lying in a single plane. A configuration as shown serves to equalize spacing from any particular point to the closest surface of said conductor without unduly restricting airflow therethrough. The conductor is peripherally dimensioned so as to overlie a substantial portion of the surface area of the evaporator 25 so that substantially all of the air inthe evaporator air stream may be electrostatically charged thereby. Insulator-like supports 36 are fixedly positioned on the base 11 of said unit and the conductor, in turn, is fixedly mounted thereon. An electrical conductor 31 connects this electrode to one terminal of a power-pack unit 32, while another conductor 33 connects the evaporator 25 to another terminal of said power-pack.

The power-pack 32, which preferably is a small enclosed assembly, may be mounted within the cabinet 1i either in the inner compartment 29, or, if desired, in the outer compartment 19, as illustrated. A power unit of this character is generally conventional and includes a high voltage transformer 24, having a primary winding 34a therein, filament transformer windings 35-36, a pair of rectifier tubes 37-38, and a pair of electrical condensers 39-40. The primary winding 34a of the transformer 34 is connected by the conductors 41 and 42 to a suitable source of electric power such as the commonly available 115 volt alternating current power supply. Conductors 43 and 44 connect the filament transformer winding 35 to the filament of tube 37, while conductors 45 and 46 connect the filament transformer winding 36 to the filament of tube 38. Conductor 46 also connects with the charging electrode conductor 31 and with con ductor 47 which, in turn, connects to one side of the electrical condenser 40. The opposite side of said condenser is connected by conductor 48 with one side of the electrical condenser 39 and the opposite side of said latter condenser is connected by conductor 49 to the collecting electrode conductor 33. A conductor 50 connects one side of the secondary winding 34b of the high voltage transformer 34 to the filament or cathode element of tube 37 while a conductor 51 also connects this end of said winding to the plate or anode element of the rectifier tube 38. The opposite side or end of the secondary winding of said high voltage transformer is connected by conductor 52 to the conductor 48 which, in turn, interconnects the electrical condensers 39 and 40. A conductor 53 connects the plate or anode element of rectifier tube 37 to the conductor 49 which, in turn, connects one side of condenser 39 with the collecting electrode conductor 33. With this arrangement the low voltage alter nating current delivered through the conductors 41 and 42 to the primary winding 34a, of the transformer 34, is stepped-up to the desired high voltage at the terminals of the secondary winding 34b of said transformer and is subsequently rectified by the tubes 37 and 38 so that one components of refrigeration polarity is impressed on the charging electrode 29 while the opposite polarity is impressed on the collecting electrode 25.

Because of the high voltage employed in devices of this character it is desirable that some safety measures be provided to minimize the possibility of electrical shock to the users thereof. Since the filter element 23 is of the replaceable type the cabinet is generally provided with an access opening through which said filter may be removed for cleaning or replacement purposes. A door or other closure member (not shown) may be mounted on the cabinet by hinges spring biased to maintain said member closed over the access opening. It is proposed that a spring-biased disconnect switch, such as is schematically indicated at 54, be inserted into the power lead :1 and arranged so that upon opening of said closure door the power circuit is interrupted thus removing the high potential from the vicinity of the electrodes 25' and 29 and permitting access to the filter element 23. Upon closing of said door the circuit would be reestablished and the device again made operative. A second springbiased switch 55 connected in series with said switch 54 and in the power lead 41 may be positioned so as to be operative by removal of the cabinet or a top closure member therein. Since this second switch is likewise connected into the main power circuit the actuation thereof will render the device inoperative and remove the high potential from the charging and collecting electrodes.

With the high potential disconnected access may be had to the interior of the cabinet for any desired purpose. It will be appreciated, therefore, that proper safeguards have now been provided and such a device may be operated with a reasonable degree of safety at all times. Since safeguards such as proposed are old and well known expedients and are susceptible of reduction into many forms they have been described only in a general way and are not intended to be claimed as part of the present invention.

As thus arranged, the electrode 29 in operation is impressed with an electrical potential of one polarity and serves as a charging electrode, while the evaporator 25 being impressed with an electrical potential of opposite polarity operates as a precipitating electrode for collecting particles of matter previously charged with the polarity of said charging electrode. In this operation the electrostatic precipitator may be said to serve as a secondary air filter with the conventional filtering element 23 function ing as a primary air filter, in which case, air moving through the filter 23 will first lose lint and other large airborne foreign particles thereto but the very fine particles of foreign matter, including the various pollens, odors, smoke, and other dust particles, will frequently pass therethrough unmolested because of the inherent characteristics of such filters which usually are designed to minimize air flow restriction rather than to complete- 1y filter out all airborne foreign matter from an air stream. After the air stream has passed through the I filter element 23 and deposited the larger of its airborne particles such as dust particles and other extraneous matter therein, it flows past the charging electrode 29 whereupon the particles of foreign matter still remaining therein are electrostatically charged with a potential corresponding in polarity to that of the charging electrode. Now when said air stream flows on into contact and heat exchange relation with the evaporator, the charged airborne particles such as dust and other foreign matter including odors and smoke will be attracted to and deposited on the surfaces thereof because said evaporator is connected to a potential of opposite polarity. Thereafter the air stream will be substantially free of all dust and other objectionable foreign particles and upon losing the heat contained therein to the evaporator 25 the air is further propelled by the blower wheel 27 as pure cooled air through the wall opening 28 back into the space being cooled. Upon recirculation of the air through the room or space being cooled, thecycle of cleaning and'coolin'g is continuously repeated andadditional airborne particles of matter may be removed each time said air passes through said filtering means.

During the course of operation of a refrigerant evaporator, as is well known in the art, moisture condenses out of the air which comes into thermal contact therewith and this moisture usually forms and collects on the surfaces of said evaporator. Ifthe evaporator is vertically positioned, the gravitational attraction wil usually be suiiicient to cause the condensate thus formed to drain to the lowest point such as pan 25a where the conduit 29a then carriesit to the pan 13a and it is then disposed of as previously described. As this condensate drains off the evaporator it serves to scrub or wash the surfaces thereof free of any loose deposits that may have been precipitated thereon and thus a very simple, substantially continuous and entirely automatically operated means is provided for cleaning the surfaces of the evaporator collecting electrode of the foreign matters electrostatically precipitated thereon.

From the above it will be apparent that a very simple and highly effective filtering arrangement has been provided for use with a portable or window-mounted type of air conditioning unit and it is to 'be understood that changes may be made in the construction shown and described without departing fromthe spirit of the invention or the scope thereof as defined in the appended claims.

What is claimed is:

1. In an air conditioning unit the combination, cornprising: a housing having openings therein opening to a space being cooled; a refrigerant evaporator cooler vertically positioned and disposed in said housing in spaced relation to one of said openings and operative for cooling air and simultaneously condensing moisture out of said air as itvpasses for cooling purposes into heat exchange relation therewith; air moving means disposed within said housing and operative for causing the flow of air from the space being cooled into heat exchange relation with said evaporator and thereafter back into the space being cooled; airborne particle-charging means positioned in the path of said air flow; airborne particle precipitating means including said evaporator disposed transversely across the path of said air flow and adapted to collect airborne particles precipitated on the surface thereof, and being arranged so that the moisture that is condensed out of said air by said evaporator will serve to wash said precipitated airborne particles from the sur- -face thereof; and means for electrically energizing said airborne particle-charging and airborne particle precipitating means to effect precipitation of airborne particles out of the air and onto said precipitating means.

2. In an air conditioning unit the combination, comprising: a casing having air inlet and outlet openings therein opening to a space being cooled; an air filtering unit disposed in said casing adjacent and across one of said air openings; a refrigerant evaporator cooler vertically positioned and disposed in said casing in spaced relation to said filtering unit and operative for cooling air and simultaneously condensing moisture out of said air as it passes for cooling purposes into heat exchange relation therewith; air circulating means disposed in said casing and connected to one of said air openings and operative for causing the flow of air from the space being cooled into heat exchange relation with said evaporator and thereafter back into the space being cooled; airborne particle-charging means disposed in the path of said air flow; airborne particle-precipitating means including said evaporator disposed transversely across the path of said air flow and adapted to collect airborne particles precipitated on the surface thereof, and arranged so that the moisture that is condensed out of said air by said evaporator Will serve to wash collections of said precipitated airborne particles from the surface thereof; and means for electrically energizing said charging means and said pre- :cipitatin "means to effect precipitation of airborne particles out or the air and onto said precipitating means.

3. In an air conditioning unit the combination, coniprising: a casing having air inlet and outlet openings therein opening to a spacebeing cooled; an air filtering unit disposed in said casing adjacent andacross one'of said air openings; a refrigerant evaporator cooler vertically positioned within said casing and disposed in spaced relation to said filtering unit and operative for cooling air and simultaneously condensing moisture out of said air it passes for cooling purposes into heat exchange relation therewith; air moving means disposed in said casing adjoining said evaporator and connected by duct means to one of said air openings and operative for causing the flow of air from a space being cooled into heat exchange relation with said evaporator and thereafterbacit into the space being cooled; an airborne particle-charging electrode disposed in the space between said air filtering unit and said evaporator; an airborne particleprecipitating electrode embracing said evaporator transversely disposed across the path of air flow in the unit and adapted to collect airborne particles precipitated on the surface thereof and arranged so that the moisture that is condensed out of said air by said evaporator serves to Wash collections of said precipitated particles fromthe surface thereof; and means for electrically energizing said electrode to effect precipitation of airborne particles out of. the air and onto said precipitating electrode.

4. In an air conditioning unit the combination, comprising: a casing having air inlet and outlet openings therein opening to a space being cooled; an air filtering unit disposed in said casing adiacent and across one of said air openings; a refrigerant evaporator cooler vertically positioned and disposed in said casing in spaced relation to said filtering unit and operative for cooling air and simultaneously condensing moisture out of said air as it passes for cooling purposes into heat exchange relation therewith; air circulating mean disposed in said casing and connected to one of said air openings and operative for causing the flow of air from the space being cooled into heat exchange relation with said evaporator and thereafter back into the space being cooled; airborne particle-charging means disposed in the path of said air flow; airborne particle-precipitating means disposed in the path of said air flow; means for electrically energizing said precipitating means to effect precipitation of airborne particles out of the said air flow and onto the surfaces of said precipitating means; said precipitating means including said evaporator transversely disposed across the path of air flow in. the unit and being arranged so that the moisture that is condensed out of said air by said evaporator serves to Wash. collections of said precipitated airborne particles from the surface thereof.

5. In an air conditioning unit the combination, comprising: a casing having air inlet and air outlet openings therein opening to a space being cooled; an air filtering element disposed in said casing adjacent and across said air inlet opening; a refrigerant evaporator cooler vertically positioned and disposed in said casing in spaced relation to said filtering element and operative for cooling air and simuitaneously condensing moisture out of said air as it passes for cooling purposes into heat exchange relation therewith; air circulating inc-ans disposed in said casing adjacent said evaporator and connected by an air duct to said air outlet opening and operative for causing the iiow of air from the space being cooled through said 1% tering element and into heat exchange relation with said evaporator and thereafter back into the space being cooled; a substantially H-shaped charging electrode disposed in the space between said filtering element and said evaporator and in the path of said air flow; a precipitating electrode disposed in the path of said air flow; means for electrically energizing said electrodes whereby the particulate matter in said air flow that is charged by said charging electrode is precipitated out of the air fiow and deposited on the surfaces of the precipitating electrode; said precipitating electrode including the refrigerant evaporator surfaces which are transversely disposed across the pathof air flow in the unit and being further arranged so that the moisture that is condensed out of said air by said evaporator will serve to wash deposits of particulate matter from the surfaces thereof.

6. In an air conditioning unit the combination, comprising: a cabinet having air inlet and air outlet openings therein opening to a space to be coo-led; a primary air filtering element disposed in said cabinet adjacent and across said air inlet opening; a refrigerant evaporator cooler vertically positioned and disposed in said cabinet in spaced relation to said primary air filtering element and operative for cooling air and simultaneously con densing moisture out of said air as it flows into heat exchange relation therewith; air circulating means immediately adjoining said evaporator and disposed on a side thereof away from said primary air filtering element; said air circulating means being connected by an air duct to said air outlet opening and being operative for causing the flow of air from a space to be cooled through said primary air filtering eienient and into heat exchange relation with said evaporator and thereafter back into the space to be cooled; a secondary air filtering means disposed in the path of said air flow and adjoining said primary air filtering element; said secondary air filtering means including an irregularly contoured charging conductor disposed in one plane, a precipitating electrode spaced therefrom, and means for electrically energizing said conductor and said electrode so that the particulate matter in said air flow that is charged by said charging conductor is precipitated out of the air How and deposited on the surfaces of the precipitating electrode; said precipitating electrode including the refrigerant evaporator surfaces which are transversely disposed across the path of air flow in the unit and being further arranged so that the moisture that is condensed out of said airby said evaporator will operate to wash deposits of particulate matter from the surfaces thereof.

7. In an air conditioning unit the combination comprising: a casing having air inlet and outlet openings therein opening to a space being cooled; an air filtering unit disposed in said casing across one of said air openings; a refrigerant evaporator cooler vertically positioned in said casing and disposed in spaced parallel relation to said filtering unit and operative for cooling air and simultaneously condensing moisture out of said air as it passes for cooling purposes into heat exchange relation therewith; air circulating means disposed in said casing and connected to one of said air openings and operative for causing the how of air from the space being cooled into heat exchange relation with said evaporator and therefter back into the space being cooled; airborne particlecharging means positioned across the path of said air flow and disposed entirely within the space between said filtering unit and said evaporator; airborne particleprecipitating means transversely disposed across the path of said air flow; means for electrically energizing said precipitating means to effect precipitation of airborne particles out of said air flow and onto the surfaces of said precipitating means; said precipitating means including said evaporator and being arranged so that the moisture that is condensed out of said air by said evaporator serves to wash collections of said precipitated airborne particles from the surfaces thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,184,782 Scott et al. Dec. 26, 1939 2,615,530 Hudson et a]. Oct. 28, 1952 2,672,206 Keist Mar. 16, 1954 

